Mike Huckabee relied on evangelical Christians and mainline conservatives to win in Georgia, edging out John McCain and Mitt Romney to take the South's biggest prize of Super Tuesday.
Georgia, with its 72 Republican delegates and stalwart base of religious voters, had been critical for Huckabee, who burst to the front ranks with his upset victory last month in the Iowa caucuses. He also cast himself as the champion of the "Wal-Mart Republican" rather than the "Wall Street" wing of the party represented by Romney.
On the Democratic side, Barack Obama coasted to victory over rival Hillary Rodham Clinton, riding a wave of support from Georgia's large black population.
Six in 10 GOP voters on Tuesday were white evangelicals and born-again Christians. Huckabee won four in 10 of their votes, according to exit polls.
Jeff Spencer was one of them. A Baptist minister in a rural area east of Savannah, Spencer said social issues were his top concern.
"Before Huckabee came up, there wasn't a real conservative, Republican view in the race as far as the right wing goes," Spencer said.
Blacks comprise about half of the Democratic primary vote in Georgia, and exit polls showed they lined up overwhelmingly behind Obama, an Illinois senator seeking to become the nation's first black president.
"Obama is just better because he makes people, like myself, get up and want to do something positive," said Felix Omigie, a black 42-year-old truck driver from Riverdale. "I can see that he is trying to tap more into the younger generation. He can relate to them."
Obama had cultivated black support in the state, speaking from the pulpit of the Rev. Martin Luther King Jr.'s church the day before the federal holiday honoring the slain civil right leader. But Clinton made him work for the win. The former first lady had the backing of prominent black leaders such as Rep. John Lewis, a civil rights hero, and former Atlanta Mayor Andrew Young.
Many voters in Georgia said Tuesday they were moved by Obama's message more than his skin color.
"I didn't want to vote for Obama just because he was black," said Jacqueline Jenkins, 42, a black administrative assistant and part-time college student who voted outside Albany. "I didn't want to vote for Hillary just because she's a woman. I think both bring a lot to the table. I just think Obama would be a better choice."
The election was the first statewide in which Georgia required a photo identification of all voters casting their ballots in person. Some sporadic problems were reported, in part because people could not wait out delays caused by the ID checks before they had to leave for work.